Pen



FIG. 1 is a lower front right perspective view of a pen showing my new design;

FIG. 2 is an upper front right perspective view thereof;

FIG. 3 is a right elevation view thereof;

FIG. 4 is a front elevation view thereof;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is a left elevation view thereof;

FIG. 7 is a rear elevation view thereof; and,

FIG. 8 is a top plan view thereof.

The stippling shown in the drawings represents a texture on the surface of the pen. 

The ornamental design for a pen, as shown and described. 